Managing the Testing Process: Practical Tools and Techniques for Managing Hardware and Software Testing

A.4. Environmental Tests

Environmental tests are those tests designed to see how the system responds to various types of insults and strenuous conditions the system will encounter in the real world. One type of such tests involves shocks and vibrations. Systems tend to get bumped, transported across rough roads, shaken, swung around in briefcases, and so forth. Rather than try to mimic these conditions exactly, the usual procedure is to mount the system under test to a shock table or vibration table, and then subject the system to certain accelerations and vibrations. The intensity of these shocks and vibrations are calibrated often in "G's" (for gravitational acceleration, like jet pilots measure tightness of turns at high speed).

Vibrations happen across various frequencies, with a gradual change usually (sweeping) across the frequencies in the course of the test. Shocks, occurring as incidents rather than over a period of time, have pulse shapes and durations. It is often somewhat difficult to imagine exactly how a particular shock or vibration test relates to an actual (potential) field incident, but most of the hardware test labs and reputable vendors have standard tests that they run. You'll need to consult an expert to understand how two different tests relate to each other, especially if they're measured in different units.

A related type of test is a drop test. Unlike the somewhat mystifying shock and vibration tests, this test involves simply dropping a system from a ...